This invention relates to a catalyst composition and to processes wherein said catalyst composition is used. More particularly, this invention relates to a supported heterogeneous catalyst composition and to processes wherein various carbonaceous materials are contacted with hydrogen and wherein said heterogeneous catalyst composition is used.
Heretofore, several hydroconversion and/or hydrotreating catalysts have been identified and used in various hydroconversion and/or hydrotreating processes. In general, the catalyst compositions heretofore proposed comprised at least one transition metal oxide or sulfide, particularly a Group VI or Group VIII metal oxide or sulfide, and the catalyst may be either supported or nonsupported. As is well known in the prior art, and in both cases, the metal oxide or sulfide may be preformed and used directly to produce the catalyst composition or the oxide or sulfide may be produced from a suitable precursor which will either decompose to or be readily converted to the metal oxide or sulfide either prior to or during the hydroconversion and/or hydrotreating operation.
As is well known in the prior art, the catalysts proposed heretofore are useful in the hydroconversion of various carbonaceous materials such as coal, lignite, peat, bitumen, heavy oils and the like to lower molecular weight products which may be either gaseous, liquid or a mixture of gaseous and liquid materials. The catalysts proposed heretofore are also useful in various hydrotreating processes such as hydrodeoxygenation, hydrodenitrogenation and hydrodesulfurization processes wherein the oxygen, nitrogen and/or sulfur contents of the feedstocks is effectively reduced. In general, the supported, heterogeneous catalysts heretofore proposed are not as active in the various hydroconversion and/or hydrotreating processes as are the nonsupported catalysts prepared by decomposition or conversion of a suitable precursor, particularly a precursor that is soluble in either the feedstock to be hydroconverted or hydrotreated or at least the solvent used in the hydroconverting or hydrotreating process. As a result, considerable effort has been devoted to the development of hydroconverting or hydrotreating catalysts produced in situ via the decomposition or conversion of a suitable precursor.
As is well known in the prior art, the effectiveness of hydroconversion and hydrotreating catalysts produced via the decomposition or conversion of a soluble precursor has been limited apparently by the respective solubility of the precursor either in the feedstock or the solvent used in the process prior to its decomposition or conversion to the corresponding metal oxide or sulfide and, perhaps, to some extent, by the temperature at which this decomposition or conversion is accomplished. While the reason or reasons for this limitation on catalytic effectiveness is not well known, it is believed to be due either to the large particle size of the active catalyst species ultimately formed directly or through agglomeration in the reaction media or to poor distribution of the active catalyst species within the reaction mixture. In any case, it is frequently difficult to control the effectiveness, particularly the catalytic activity, of a catalyst which is prepared via the decomposition or conversion of a precursor compound. These catalysts have not, therefore, always resulted in maximum or optimum effectiveness when used in the various hydroconversion and hydrotreating operations. There is, then, a need for an improved catalyst composition which will be more effective in the various hydroconversion and hydrotreating processes.